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  <title>ol-ext: Undo/redo</title>
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  <a href="https://github.com/Viglino/ol-ext" class="icss-github-corner"><i></i></a>

  <a href="../../index.html">
    <h1>ol-ext: Undo/redo custom</h1>
  </a>
  <div class="info">
    <p>
      <i>ol/interaction/UndoRedo</i> is an interaction to handle undo/redo on a map.
    </p>
    This example shows how to use the <i>define()</i> method to define a custom action.
    <ul>
      <li>
        The <i>push()</i> method lets you push a custom action in the undo list.
      </li>
      <li>
        You can use the <i>blockStart() / blockEnd()</i> methods to stack many actions in one undo.
      </li>
    </ul>
    <p>
      For undoing features properties, look at the 
      <a href="map.interaction.undoredo2.html">undo/redo attributes exmaple</a>.
      <br/>
      For more information on UndoRedo interaction look <a href="map.interaction.undoredo.html">at this example</a>.
    </p>
  </div>

  <!-- Map div -->
  <div id="map" style="width:600px; height:400px;"></div>

  <div class="options" >
    <b>Set style:</b>
    <ul>
      <li>
        <label>color:</label>
        <select id="color">
          <option value="rgba(255,0,0,.5)">red</option>
          <option value="rgba(0,255,0,.5)">green</option>
          <option value="rgba(0,0,255,.5)">blue</option>
        </select>
      </li>
      <li>
        <label>width: </label>
        <input id="width" type="number" min="0" step="1" style="width:5em;" value="2" />
      </li>
      <li>
        <button onclick="setStyle()">OK</button>
      </li>
    </ul>
  </div>

  <script type="text/javascript">

    // GeoJSON layer
    var vectorSource = new ol.source.Vector({
      url: '../data/departements.geojson',
      format: new ol.format.GeoJSON(),
      attributions: [ "&copy; <a href='https://www.insee.fr'>INSEE</a>", "&copy; <a href='https://www.data.gouv.fr/fr/datasets/geofla-r/'>IGN</a>" ],
    });
    var listenerKey = vectorSource.on('change',function(e){
      if (vectorSource.getState() === 'ready') {
        ol.Observable.unByKey(listenerKey);
        // Clear undo/redo on load
        undoInteraction.clear();
      }
    });
    var vector = new ol.layer.Vector( { 
      source: vectorSource,
      style: function (f) {
        return [
          style, 
          new ol.style.Style({
            text: new ol.style.Text({
              text: f.get('id'),
              font: 'bold 11px sans-serif',
              stroke: new ol.style.Stroke({ width: 1.5, color: [255,255,255] }),
            })
          })
        ]
      }
    });

    // The map
    var map = new ol.Map ({
      target: 'map',
      view: new ol.View ({
        zoom: 6,
        center: [180000, 6060000]
      }),
      layers: [
        new ol.layer.Tile({ source: new ol.source.OSM() }),
        vector
      ]
    });

    // Main control bar
    var mainbar = new ol.control.Bar();
    map.addControl(mainbar);

    // Editbar
    var editbar = new ol.control.EditBar ({
      source: vector.getSource(),
      edition: false,
      interactions: { Select: true, Info: false, Split: false, Offset: false }
    });
    mainbar.addControl(editbar);

    // Undo redo interaction
    var undoInteraction = new ol.interaction.UndoRedo();
    map.addInteraction(undoInteraction);

    // Add buttons to the bar
    var bar = new ol.control.Bar({ 
      group: true,
      controls: [
        new ol.control.Button({
          html: '<i class="fa fa-undo" ></i>',
          title: 'undo...',
          handleClick: function() {
            undoInteraction.undo();
          }
        }),
        new ol.control.Button({
          html: '<i class="fa fa-repeat" ></i>',
          title: 'redo...',
          handleClick: function() {
            undoInteraction.redo();
          }
        })
      ]
    });
    mainbar.addControl(bar);

    /* undo/redo custom */
    var style;
    // Define undo redo for the style
    undoInteraction.define(
      'style', 
      // undo function: set previous style
      function (s) {
        style = s.before;
        vector.changed();
      },
      // redo function: reset the style
      function(s) {
        style = s.after;
        vector.changed();
      }
    );
    // undo/redo custom
    function setStyle() {
      var before;
      if (style) before = style.clone();
      style = new ol.style.Style({
        stroke: new ol.style.Stroke({ width: Number($("#width").val()), color: "#f00" }),
        fill: new ol.style.Fill({ color: $("#color").val() })
      });
      vector.changed();
      // use blockStart / blockEnd to stack many undo in a same action
      // undoInteraction.blockStart();
      // Add undo style action
      undoInteraction.push('style', { before: before, after: style });
      // undoInteraction.blockEnd();
    }
    setStyle();

  </script>

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